Mandrel for tire tubes



Jan, 27. 1925.

C. E. LOWE MANDREL FOR TIRE TUBES Filed Aug. 21, 1922 INVENTOR. Uyde E. Lowg.

ATTORNEY.

Patented Jan. 27, 1925.

UNITED STATES CLYDE E. LOWE, OF CLEVELAND, OHIO.

MANDREL FOR TIRE TUBES.

Application filed August 21, 1922.

To all whom it may concern:

Be it known that I, CLYDE E. Lown, a citizen of the United States, residing at Cleveland, in the county of Guyahoga and State of Ohio, have invented a certain new and useful Improvement in Mandrels for Tire Tubes, of which the following is a full,

\ clear, and exact description, reference being had to the accompanying drawings.

This invention relates to the manufacture of pneumatic tire tubes and has for its purpose the provision of a seamless, rigid, curvilinear, discontinuous, hollow mandrel for the forming and curing of inner tubes of pneumatic tires which shall fit the casings more exactly than previous tubes. Owing to the impossibility of securing any other kind of mandrel such tubes have. always heretofore been made of circular cross section, while the casings in which they are used are ordinarily of an ovate cross section which leads to wrinkling of the tube at the innerside with all the attendant disadvantages. The main object of my invention is the provision of a new and improved type of mandrel which shall possess the shape desired, shall be smooth and seamless, shall be light and of small heat capacity, and shall be inexpensive. Other objects of the invention are the provision of a new and improved process for producing such a mandrel; while further objects and advantages will become apparent as the description proceeds.

In the drawings accompanying and forming a part of this application I have shown my improved mandrel together with the preferred process and apparatus for producing the same, although it will be understood that these drawings are intended to be merely illustrative and not limiting upon me. Fig. 1 illustrates a complete mandrel embodying my improvements; Fig. 2 is a sectional view corresponding to the line 2 2 of Fig. 1; Fig. 3 illustrates the first step of the process; Figs. 4 and 5 illustrate the preferred form of clamping member employed in the succeeding step; Fig. 6 illustrates the preferred form of bending and forming machine; and Figs. 7 and 8 are sectional views corresponding to the lines 77 and 8-8 respectively of Fig. 6.

My improved tire-mandrel consists of a hollow wrought-metal tube bent to circular form but subtending slightly less than 360, each portion of said mandrel being ovate in cross section with its smaller end inward.

Serial No. 583,341.

This mandrel is preferably made from a single piece of seamless tubing so that the tubes cured thereon shall be smooth and uniform while their ovate section combined with their curvilinear shape enables the ends to be brought together and cemented into an endless tube which exactly fits a tire casing without twisting, wrinkling, or stretching.

The preferred mode of producing this mandrel from an ordinary seamless tube is as follows: A cylindrical tube 1 of suitable length, thickness and diameter is inserted between dies 22 of approximately the desired shape, butonly for a sufiicient distance from the end to enable the insertion of a spreader or triplet 3 and a plug 4:. This plug consists of a body portion adapted to it substantially into the end of the mandrel, one face of the same having a longitudinally threaded stud 5 projecting therefrom and one corner adjacent said stud being cut away as at 6. Cooperating with this plug is a collar member 7 complementary thereto and adapted to receive the end of the tube after which the collar is clamped thereon by a suitable nut 8. i

The tube is then simultaneously formed and bent in the following manner: Rigidly keyed to a shaft 10 is a split spool made of side pieces 11 secured together by bolts 12 and having a peripheral groove 13 corresponding in contour to that portion of the mandrel which lies inside its region of greatest thickness. Outside this point the lips of the spool preferably project in the form of flat sided flanges ll between which is mounted the longitudinally movable bar 15. The side of said bar which faces said groove is itself hollowed out in the form of a semi-cylindrical channel 16 which substantially fits the tube 1, and the other side preferably runs against suitable anti-friction rollers 17-1.7. At one point in the periphery of the spool the walls of the groove are notched for the reception of the clamp 7. The triplet is rigidly attached to a rod 18 suitably secured to some part of the machine frame so as to hold the triplet sta tionary between the spool and follow bar. As shown in Fig. 8, the triplet 3 has the exact contour of the interior of the mandrel.

The end portion of the tube 1 having been suitably shaped by the dies 2 2, the triplet 3 and plug 4 are inserted therein after which the end of the tube is hammered over the notch 6 and the clamp 7 fastened llll' thereonhbyuther-nut8. The tube isthen introduced into thergroove of thezspoolnthe follow bar applied, and the rod 18 fastened against movement, after which the spool is slowly rotated so as to draw the tube past the triplet, simultaneously imparting thereto the circular shape and ovate section desired. It is then removed by takingthe spool apart, removing the clamp '7 and either restoring the bent portion to aireven surface or sawing off thew/ends It will be understood that I do-not limitmyself: to thisexaet curvature'ofmy improved-- mandrel; nor -to any aexact angular extend neither do I restrict myself tothisexa ct pro-- cessi-of-making-the same, nor do I limitthis process to the marking of mandr'elsof this cross section only ';-nor do I limit inyself in any:other manner except as specifically recited: in the *annexed claims It is noted-,-

however; that-asheet metal mandrel is far superior to lacast iron "one owing r :to its higher lheatconductivity land I itssmaller:

heat capacity which leadsto a better curing ofthe tubesrin addition to the greater ease: of: handling andwthat theabsence=of seams and welding: produces 3 gr eater: uniformity;

Having :thus described my invention, what I clainrisz 1. A seamless wrought+metalmandrel for tire tubes having :a' curvilinear form subtend ing *thei greater part of a circle lmt-less=than 360, each'npor-tion of said mand-rehbein-g ovate .-in-:rcross=section with its smaller end inward. V

2 1A hollowone. piece metal mandrel for tire tu'bes" made 1 in curvilinear rorm each portion of said mandrel being :ovate in cross secti'oii'witli itsi smaller-end at the inside of the'curve. r

3'. A seamless wroughtmandrel, for=tires and tire'tubes and similar articles, having a curvilinear form an'd an ovate cross SBGtl'OIIa' 4. A seamless wroughtmandrel, for-tires andfitire tubes 'and similar articles, having a curvilinear form, .subt'endinge the greater part: of' a circley-and;ihaving an ovate *cross section.

5. A seamless wrought mandrelafor-tires ,anditire tubes and similar articles; having a' curvilinear .foi'ingv subtending the greater partwot' a circle' but not a complete circle, and having an ovate cross section. a

6. A seamless:wrought mandrelyfor tires andti-re tubes and similar articles, having a curvilinear =forni, and air ovate cro'sssec tion formed wit-lithe small: end =of=the oval directed *inwa'rdly. I

7. A seam'lesswvrouglit mandrel for tires and tire tubes andvsimil'ararticles, *having a: curvilinear form, i subtending .ithe greater part-"of circle, and having an ovate cross section with the sm'a'ller end of the oval di-' rected inwardly. @r

8. A seamless wrought mandrel, for tires and tire tubes and'similar*articlesgliaving a curvilinear form, subtending the greater part of a circle but not an entire circle, and havingan ovate-cross section with the smaller end of the oval directed inwardly.

9.'A hollow onepiece mandrel, for tires and tire tubes and similar articles, having a curvilinear form and'an ovate fross section.

10. A hollow one-piece mandrel,ior tires and tire tubes 1 and similar articles, ha ving'a curvilinear form, *subtending y the greater part of a circle, and having an-ovate cross curvilinearfoiin, subtending ,the greate'l part or a Cll'ClQ, andhaiving alt-ovate cross: SBCtlOII with the smaller end of the oval directed inwardly.=

11. A hollowonepiecemandrel, for tires and tire tubes andsimilar articles, having a curvilinear form subtending the greater part of a circle but=not an-entire'cirele, and havingwan ovate cross section 'with the smallerend of the oval directed inwardly.

15. A mandrel for tire tubes-consisting 'of a single seamless colddrawn metal-tube ot arcuate shapesubtend-ing at least aboi1t300 of arc.

16. A seamless one-piecemandrel for tire tubes made of a single cold 'drawn metal tubesubtending the greater part of a circle and having its endsspacedapart.

17. A mandrel tortire tubescomprising a seamless metal 1 tube of arcuate shape sub-' tendingat least the greatcr part of a circle, the portions ot' thetuhe which consistutc thesides of the annulus having a smaller degree oftransverse curvature than thcportions which constitutethc inner and outcr edges of such annulus.

18. A mandrel for tiretubes comprising a seamless metal 'tube'of oblong cross section formed into an are which subtends the greatei part of a circle,' =the cur ature of such are lying in the plane'of the'maximum transverse curvature ot'thewallsot lhe'tuhe and said tube having portions of diminished transverse curvature facinglaterall' of such are.

In testimony whereof,- I hereunto alli at'my si gn ature; i

CLYDE -I*l. LOWE. 

